Massive carotid body tumor

Xiaoxiao Li, MD1; Shujun Qiu, MD1; Xi Zhao, MD2
1 Universal Medical Imaging Diagnostic, Shanghai, P. R. China
2 Siemens Healthineers, China

2021-03-01

A 45-year-old female patient, who has had a slow-growing, painless and nonpulsatile mass on the left side of her neck for the past 20 years, was presented to the hospital. She was asymptomatic and her past medical history was unremarkable. A CT angiography (CTA) was requested for pre-operative evaluation.

CTA images revealed a large, hypervascularized and heterogeneous mass in the left carotid space, measuring 11.8 x 9.6 cm in size, and extending from the thoracic inlet up to the parapharyngeal space. The left common carotid artery (CCA) was severely encased. The bifurcation, as well as the course of the internal (ICA) and external (ECA) carotid arteries were not seen. The left internal jugular vein (IJV), the external jugular vein (EJV), as well as multiple tortuous collaterals were displaced posterolaterally and were adherent to the mass. 

The Circle of Willis (COW) was well established, with sufficient collaterals. There was no indication of bone erosion at the base of the skull. The vertebral arteries were bilaterally patent. The diagnostic impression was that of a left carotid body tumor (CBT), Shamblin grade III. The patient subsequently underwent tumor resection, along with ligation of the left CCA, IJV and EJV. The histopathology report concluded a paraganglioma. The postoperative recovery was uneventful. There was no evidence of brain ischemia after surgery. A follow-up CTA showed a well-established COW with a decreased caliber of the distal right middle cerebral artery (MCA).

MPR and cVRT images show the comparison between prior to and after surgery of a large, hypervascularized and heterogeneous mass.

Courtesy of Universal Medical Imaging Diagnostic, Shanghai, P. R. China

Fig. 1: MPR (Figs. 1a and 1d) and cVRT (Figs. 1b, 1c, 1e, and 1f) images show the comparison between prior to (Figs. 1a-1c) and after surgery (Figs. 1d–1f). A large, hypervascularized and heterogeneous mass (Fig. 1a) in the left carotid space is completely resected (Fig. 1d). In the arterial phase (Figs. 1b and 1e), the left CCA is shown to be severely encased (Fig. 1b) and is ligated along with the resection of the tumor (Fig. 1e). In the venous phase (Figs. 1c and 1f), the left IJV, EJV and multiple tortuous collaterals are shown to be displaced by, and adherent to, the mass (Fig. 1c) and are ligated as well (Fig. 1f).

MIP images show a well-established COW pre- and post-surgery. The distal right MCA shows a decreased caliber after surgery.

Fig. 2: MIP images show a well-established COW pre- (Fig, 2a) and post-surgery (Fig. 2b). The distal right MCA shows a decreased caliber after surgery.

CBTs are slow-growing, rare neoplasms arising from the chemoreceptor cells of the carotid bulb. Surgical excision is the treatment of choice. These tumors can pose a great technical challenge for surgeons due to their location and their hypervascularization. The evaluation of imaging features and cerebral collateral circulation is critical for the selection of treatment methods. CTA can define the size and margins of the tumor, the adherence of the tumor to the peripheral tissues and the extent of the vascularization. 

With the ultra-fast scanning technique provided by a dual source CT scanner, SOMATOM® Force, a pure arterial phase can be acquired, providing an unobscured view of arterial vasculature for an optimal evaluation. Image demonstration using cinematic volume rendering technique (cVRT) provides a better 3D perspective with improved depth and shape perceptions, enabling a lifelike demonstration.

Scanner

Scan area

Head & Neck
(Pre-surgery)

Head & Neck
(Post-surgery)

Scan mode

Spiral

(Arterial/venous phase)

Spiral

(Arterial/venous phase)

Scan length

321 / 321 mm

306 / 306 mm

Scan direction

Caudo-cranial/

Cranio-caudal

Caudo-cranial/

Cranio-caudal

Scan time

1.7 / 1.7 s

1.6 / 1.6 s

Tube voltage

80/80 kV

80/80 kV

Effective mAs

190/205 mAs

190/207 mAs

Dose modulation

CARE Dose4D

CARE Dose4D

CTDIvol

3.9/4.2 mGy

3.9/4.2 mGy

DLP

138.7/149.7 mGy cm

133.4/145.2 mGy cm

Rotation time

0.25/0.25 s

0.25/0.25 s

Pitch

1.2/1.2

1.2/1.2

Slice collimation

128 x 0.6/128 x 0.6 mm

128 x 0.6/128 x 0.6 mm

Slice width

0.75/0.75 mm

0.75/0.75 mm

Reconstruction increment

0.5/0.5 mm

0.5/0.5 mm

Reconstruction kernel

Bv40/Bv40

Bv40/Bv40

Contrast

350 mg/mL

350 mg/mL

Volume

65 mL + 35 mL saline

65 mL + 35 mL saline

Flow rate

4.5 mL/s

4.5 mL/s

Start delay

Bolus tracking in the aortic arch at 100 HU 
with an additional 3 s for the first scan
+ 8 s after the first scan

Bolus tracking in the aortic arch at 100 HU
with an additional 3 s for the first scan
/ + 8 s after the first scan